%0 Journal Article
%T STRUCTURE EVOLUTION OF DIRECTIONALLY SOLIDIFIED Ti--43Al--3Si ALLOY II. Microstructure Evolution in the Steady--State Growth Region<br>
%A LI Xinzhong
%A FAN Jianglei
%A GUO Jingjie
%A SU Yanqing
%A FU Hengzhi
%A <br>
%J 金属学报
%D 2009
%I 
%X Microstructure evolutions in the steady--state growth region of directionally solidified Ti--43Al--3Si (atomic fraction, %) alloy were studied at growth rates of 3---100 μm/s. There are four main phase transitions during directional solidification: L→Ti5Si3, L→α+Ti5Si3, α→α2(Ti3Al)+γ(TiAl) and α2→γ+Ti5Si3, especially, the eutectic reaction of α and Ti5Si3 is the typical solidification behavior. When the growth rate exceeds 20 μm/s, another phase transition of L→γ+Ti5Si3 also happens. With increase of growth rate, the steady--state growth microstructure changes from coarse cells to fine cells, to cellular dendrites and then to dendrites. The Ti5Si3 phase stabilizing $\alpha$ phase distributes in the α matrix at a low growth rate, and in the solidified γ matrix at a relatively high growth rate, which is unfavorable in seeding. When the growth rate is 10 μm/s, the distance needed to reach steady--state region becomes shorter, which is favourable in seeding for the present alloy.
%K Ti--43Al--3Si alloy
%K directional solidification
%K microstructure
%K steady--state growth<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=AB188D3B70B071C57EB64E395D864ECE&jid=B061E1135F1CBDEE96CD96C109FEAD65&aid=CAAC4E03DF04EA2E01C14C31D140CBC2&yid=DE12191FBD62783C&vid=94E7F66E6C42FA23&iid=38B194292C032A66&sid=51C74DF6A16DA45B&eid=C2F76551C0111538&journal_id=0412-1961&journal_name=金属学报&referenced_num=0&reference_num=16